Viscoelastic Coupling Dampers (VCDs) and Viscoelastic-Plastic Coupling Dampers (VPCDs) for Enhanced Efficiency and Resilience of High-Rise Buildings

New damping systems - the Viscoelastic Coupling Damper (VCD) and Viscoelastic-Plastic Coupling Damper (VPCD) - have been developed to improve the performance of tall, reinforced concrete (RC) buildings subject to both wind and earthquake loads. VCDs are introduced in lieu of RC coupling beams to take advantage of differential shear deformations between adjacent walls during lateral loading of the structure. The VCDs utilize multiple viscoelastic (VE) material layers that are bonded to alternating steel plates with each consecutive steel layer extending out to the opposite side and anchored into the walls using a number of alternate connection details. When the building is subject to frequent or design level wind storms or low level earthquakes, the damper exhibits both a displacement-dependent elastic restoring force providing coupling to the walls and a velocity-dependent viscous force, providing supplemental damping to the building. In regions of severe seismicity, a ductile "fuse" element can also be included in the damper to enhance its performance. The "fuse" is capacity designed such that if predefined load levels are reached in the damper during extreme seismic loading, connection elements act as force-limiting members and prevent damage from occurring in adjacent structural elements. The response during severe earthquakes is viscoelastic at small amplitudes and becomes plastic once the connections start yielding, resulting in what is termed a Viscoelastic-Plastic (VEP) hysteresis. Replaceable connections are utilized to allow for repair or replacement after an earthquake. This paper describes the Viscoelastic and Viscoelastic-Plastic response of this new damping system and provides some examples of the design concept and applications of this technology.